Refactor: Composable disentangling (#5695)

## Summary

Prerequisite refactor/cleanup to use a global store instead of having
nodes throw up events to a parent component that stores a reference to a
singleton service that itself bootstraps and synchronizes with a
separate service to maintain a partially reactive but not fully reactive
set of states that describe some but not all aspects of the nodes on
either the litegraph, the vue side, or both.

## Changes

- **What**: Refactoring, the behavior should not change.
- **Dependencies**: A type utility to help with Vue component props

## Review Focus

Is there something about the current structure that this could affect
that would not be caught by our tests or using the application?

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5695-Refactor-Composable-disentangling-2746d73d365081e6938ce656932f3e36)
by [Unito](https://www.unito.io)

src/renderer/extensions/vueNodes/composables/useNodePointerInteractions.ts

@@ -0,0 +1,93 @@
+import { type MaybeRefOrGetter, computed, ref, toValue } from 'vue'
+
+import type { VueNodeData } from '@/composables/graph/useGraphNodeManager'
+import { useCanvasInteractions } from '@/renderer/core/canvas/useCanvasInteractions'
+import { layoutStore } from '@/renderer/core/layout/store/layoutStore'
+import { useNodeLayout } from '@/renderer/extensions/vueNodes/layout/useNodeLayout'
+
+// Treat tiny pointer jitter as a click, not a drag
+const DRAG_THRESHOLD_PX = 4
+
+export function useNodePointerInteractions(
+  nodeDataMaybe: MaybeRefOrGetter<VueNodeData>,
+  onPointerUp: (
+    event: PointerEvent,
+    nodeData: VueNodeData,
+    wasDragging: boolean
+  ) => void
+) {
+  const nodeData = toValue(nodeDataMaybe)
+
+  const { startDrag, endDrag, handleDrag } = useNodeLayout(nodeData.id)
+  // Use canvas interactions for proper wheel event handling and pointer event capture control
+  const { forwardEventToCanvas, shouldHandleNodePointerEvents } =
+    useCanvasInteractions()
+
+  // Drag state for styling
+  const isDragging = ref(false)
+  const dragStyle = computed(() => ({
+    cursor: isDragging.value ? 'grabbing' : 'grab'
+  }))
+  const lastX = ref(0)
+  const lastY = ref(0)
+
+  const handlePointerDown = (event: PointerEvent) => {
+    if (!nodeData) {
+      console.warn(
+        'LGraphNode: nodeData is null/undefined in handlePointerDown'
+      )
+      return
+    }
+
+    // Don't handle pointer events when canvas is in panning mode - forward to canvas instead
+    if (!shouldHandleNodePointerEvents.value) {
+      forwardEventToCanvas(event)
+      return
+    }
+
+    // Start drag using layout system
+    isDragging.value = true
+
+    // Set Vue node dragging state for selection toolbox
+    layoutStore.isDraggingVueNodes.value = true
+
+    startDrag(event)
+    lastY.value = event.clientY
+    lastX.value = event.clientX
+  }
+
+  const handlePointerMove = (event: PointerEvent) => {
+    if (isDragging.value) {
+      void handleDrag(event)
+    }
+  }
+
+  const handlePointerUp = (event: PointerEvent) => {
+    if (isDragging.value) {
+      isDragging.value = false
+      void endDrag(event)
+
+      // Clear Vue node dragging state for selection toolbox
+      layoutStore.isDraggingVueNodes.value = false
+    }
+
+    // Don't emit node-click when canvas is in panning mode - forward to canvas instead
+    if (!shouldHandleNodePointerEvents.value) {
+      forwardEventToCanvas(event)
+      return
+    }
+
+    // Emit node-click for selection handling in GraphCanvas
+    const dx = event.clientX - lastX.value
+    const dy = event.clientY - lastY.value
+    const wasDragging = Math.hypot(dx, dy) > DRAG_THRESHOLD_PX
+    onPointerUp(event, nodeData, wasDragging)
+  }
+  return {
+    isDragging,
+    dragStyle,
+    handlePointerMove,
+    handlePointerDown,
+    handlePointerUp
+  }
+}